Allow using .class-name * selector to initiate the plugin for all chil...

...dren of an element

test case:

```js

     $('.some-div *').tipr({
          'speed': 300,
          'mode': 'top'
     });
```

notice how * is used to apply it to all children. this is good because you only need to place the `data-tip` attribute in the child elements.

If accepted, i will leave minification up to you. thanks for the lightweight and awesome plugin. its a breeze to work with.